JPH01227669A - Vibration wave motor - Google Patents

Abstract

PURPOSE:To reduce the cost and size of a vibration wave motor by bringing an annular stator in which a vibrator is adhered to an annular resonator into pressure contact with an annular rotor, and providing a pressing mechanism in which its pressing force is adjustable. CONSTITUTION:In a vibration wave motor, a stator 1 is mounted on a stationary shaft 8 in which threaded parts 7 are engaged at both ends thereof. A compression spring 5 for pressing the stator 1 and the rotor 9 is provided, and mounted with a spring washer 6 engageable with the threaded part 7. The pressure of the spring 5 is altered by varying the position of the washer. Thus, a bending traveling wave is generated at the stator 1, thereby generating a vibration having an elliptical orbit. This vibration is converted to the rotary motion of the rotor 9 by designing the rotor 9 having structure for pressing the rotor 9. The rotor 9 is formed of an engineering plastic member having excellent wear resistance on its lining face 10 of the part in contact with the stator 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vibration wave motor, and more particularly to a vibration wave motor using an ultrasonic wave as a driving source.

[Conventional technology]

First, the principle of a general vibration wave motor will be explained. Fig. 2 is an explanatory diagram showing how the stator vibrates due to traveling waves, Fig. 6 is a front view including a partial cross section showing an example of a vibration wave motor having a conventional Calo pressure mechanism, and Fig. 7 is a vibration of the conventional example. It is a block diagram which shows the whole driving situation when two wave motors are used.

The conventional vibration wave motor shown in FIG. 6 is of a traveling wave rotation type or an annular type, and has an annular shape similar to that of the stator 1 on the back side of an annular elastic diaphragm (stator 1). The piezoelectric elements 2 are bonded and integrated. The same annular moving body (rotor 9) is pressed against the surface of the stator 1 with a predetermined pressure by means such as a compression spring 5.

The sliding surface of the rotor 9 is provided with 10 liner/gating surfaces made of a wear-resistant material, such as a composite plastic material with aromatic polyamide fiber as an optical filler and polyurethane resin as a matrix. The J-stator 1 completely prevents wear. An electric signal for a vibration wave motor is input to the piezoelectric element 2, and a traveling wave flexural vibration is generated in the system stator l due to the bimetallic effect. As shown in the explanatory diagram of FIG. 2, the traveling wave on the stator 1 draws an elliptical trajectory when focusing on one point CK on the surface of the stator 1. Since the lining surface 10 is in contact with the apex of the traveling wave of the stator 1, the rotor 9 can be moved by friction in the direction of the trajectory around the apex of the ellipse, so the rotor 9 is moved in the opposite direction to the traveling direction of the traveling wave. Proceed in the direction of arrow F. Therefore, the rotor 9 rotates opposite to the direction of travel of the traveling wave on the stator 1, and its rotational speed is related to the speed of the elliptical trajectory.

By the way, when considering the case where a plurality of vibration wave motors are driven at the same time, conventionally, the number of drive devices is equal to the number of vibration wave motors. This is due to the following reasons.

Flexural vibrations that occur in the stator 1 occur only when the frequency of the traveling wave is equal to or close to the resonant frequency of the stator 1. Therefore, the frequency of the input electrical signal must be the resonant frequency specific to the stator 1. Must be. The following two factors can be cited as factors that influence this resonant frequency. One is the shape and dimensions of the stator 1, and the other is the pressing force between the stator 1 and the rotor 9.

However, it is difficult to manufacture the stator 1 of each vibration wave motor with exactly the same shape and dimensions due to machining errors when manufacturing the motor.

Also, in FIG. 6, the conventional stator 1 and rotor 9
Paying attention to the mechanism that presses and contacts the fixed shaft 8', the stator 1. Compression spring for pressurization5. It is comprised of a spring washer 6' that limits the entire length of the compression spring 5. The length of the compression spring 5 is determined at the time of design because the spring washer 6' is fixed to the fixed shaft 8'.
Therefore, the magnitude of the pressing force between the stator l and the rotor 9 cannot be changed either.

From the above two points, it is difficult to make the resonant frequencies of the stators 1 of a plurality of vibration wave motors the same. For this purpose, as shown in the configuration diagram of FIG. 7, the conventional drive device A3゜B3 that drives the vibration wave motor generates a unique resonance frequency in the stator Alt''1 of the plurality of vibration wave motors A and H. A device that has oscillators A4 and B4 and therefore uses a plurality of vibration wave motors requires as many drive devices as the number of vibration wave motors.

[Problem to be solved by the invention]

As described above, conventionally, in a device having a plurality of vibration wave motors, the resonant frequency of the stator is not the same for each vibration wave motor. Therefore, in order to drive two or more vibration wave motors, it is necessary to prepare drive devices that generate input electric signals for the vibration wave motors for only the types of frequencies input to the vibration wave motors. Therefore, it has drawbacks such as high cost and large space requirements.

[Means to solve the problem]

The vibration wave motor of the present invention has an annular stator having a structure in which a vibrator for converting electric vibration having a vibration waveform into mechanical vibration and an annular resonator are bonded together, and an annular rotor, which are brought into pressure contact with each other. The annular rotor is fixed on the shaft, the annular stator is fitted adjacent to the annular rotor so as to be movable in the axial direction, and the fixing shaft has a threaded portion at the end thereof, and the fixed shaft has a threaded portion on the male threaded portion. A spring washer having a mating female thread portion and screwed onto the fixed shaft, and a compression spring provided between the annular stator and the spring washer to adjust the pressing force on the annular stator. It is equipped with a possible pressurizing mechanism.

[For production]

Fig. 3 is a graph showing the experimental results of the relationship between the pressing force between the stator and rotor and the resonant frequency of the stator, and Fig. 4 shows the stator in two vibration wave motors.

An explanatory diagram showing the relationship between the pressing force between the rotors and the resonant frequency of the stator. In the configuration of pressurized contact,
The resonance frequency P of the stator was 5 mm as shown in Experiment 6 in FIG. 3, and the rotor was made of aramid engineering plastic on its sliding surface. Therefore, by changing the position of the spring washer 6 to a screw and changing the pressing force, the resonant frequency of the stator 1 can be changed to the stator 1.
can be adjusted without changing the shape and dimensions of the

Now, consider the stator resonance frequency characteristics α and β of the vibration wave motors A and B shown in the explanatory diagram of FIG. 4. At the same pressing force M, the stator resonance frequency S of the vibration wave motor A is smaller than the stator resonance frequency Q of the vibration wave motor B. In this case, change the position of the spring washer 6 to determine the length of the compression spring 5. : By adjusting and increasing the pressing force of the stator 1 and rotor 9 of the vibration wave motor A to the pressing force N, and decreasing the pressing force of the vibration wave motor B to the pressing force, the resonance frequency can be made the same. .

Therefore, as shown in the configuration diagram of FIG. 5, A and B.

It is possible to drive two vibration wave motors by the drive device C3 that generates the same frequency deposit.

〔Example〕

FIG. 1 is a front view including a partial cross section of an embodiment of the present invention, and FIG. 5 is a configuration diagram showing a situation in which two vibration wave motors according to the embodiment are driven by one drive device.

In FIG. 5, both the left and right end surfaces of the roller 12 molded into a cylindrical mold are referred to as a rotor 9, and stators Al, Blj-
Make pressure contact. The fixed shaft 8 passes through the inside of the roller 12, and the roller 12 can rotate once around the fixed shaft 8.

The front view showing the basic configuration of this embodiment in FIG. 1 is shown in FIG. 5, which is a detailed view of both sides of the companion roller 12. Stator AI, BL
i Attach the mount. Furthermore, a compression spring 5 is provided for the stators Al and Bl to pressurize the rotor 9.
a spring washer 6 having a female threaded portion on the inside so as to be screwed into the spring washer 6;
By attaching p and changing this position kf, the pressing force of the compression spring 5 is increased to kW. To show specific numerical values in Fig. 1, the stator 1 is made of an elastic member, phosphor bronze, and has an original outer diameter of 29 mrrL%, an inner diameter of 21 mm, and a thickness of 5 mm.
An electric vibration signal, for example, an ultra-f wave 1rX71 of 51 KHz 170 Vpp is applied to a piezoelectric element 2 of thickness Q and 5 mm bonded to the end face of the stator 1 to excite a bending traveling wave in the stator 1. As shown in the explanatory diagram of FIG. 2, the generation of the stator IK bending traveling wave causes vibrations having a p-elliptical orbit 21. This vibration is transferred to the rotor 9
By adopting the above-mentioned pressurizing structure that presses the rotor 9
Convert to rotational motion. At rotor 9, stake 1
For the lining surface 10, which is the part that comes into contact with the lining surface 10, an engineering plastic member with excellent wear resistance is used, and a processing method is applied to achieve a surface roughness of 08S.

[Effects of the Invention] As explained above, the present invention applies pressure to an annular stator and an annular rotor having a structure in which a vibrator that converts electrical vibration having a vibration waveform into mechanical vibration and an annular resonator are bonded together. In a device using multiple vibration wave motors, by providing a pressure mechanism that can be brought into contact with each other and whose pressure force can be adjusted, a drive device that generates input electrical signals for the vibration wave motors can be used. Multiple vibration wave motors can be driven by a single drive device that generates the same frequency without having to prepare only the types of frequencies to be input into the motor, reducing costs and downsizing by reducing the number of drive devices. is effective.

[Brief explanation of the drawing]

Is Fig. 1 a partial cross section of an embodiment of the present invention? Fig. 2 is an explanatory diagram showing how the stator vibrates due to traveling waves, Fig. 3 is a graph showing the experimental results of the relationship between the pressing force between the stator and rotor and the resonant frequency of the stator, and Fig. 4 is an explanatory diagram showing the relationship between the Calo pressure between the stator and rotor and the resonant frequency of the stator in two vibration wave motors, and FIG. A configuration diagram showing the situation, FIG. 6 is a front view including a partial cross section showing an example of a conventional vibration wave motor having a pressurizing mechanism, and FIG. 7 is a configuration diagram using two conventional vibration wave motors.
This is a configuration diagram showing the driving situation in case 110-. 1. la, lb...Stator, 2...
Piezoelectric element, 3... Cushion, 4...
Stator board, 5... Compression spring, 6, 6'...
...Spring washer, 7...Threaded part, 8.8'.
... Fixed shaft, 9 ... Rotor, 10 ...
... Lining surface, 11 ... Bearing, 12 ...
...low 2.13...housing, 21...
...Elliptical orbit, C, D...One point on the stator surface, P...Resonant frequency characteristics of the stator, Q, R
,,S...Resonance frequency of the stator, L. M, N... Pressure force between stator and rotor, a...
...Resonant frequency characteristics of vibration wave motor A, β...
...Resonant frequency characteristics of vibration wave motor B, 14a, 14b
, 14c... Drive device, 15a, 15b, 15
C: Oscillator. Agent Patent Attorney Susumu Uchihara Page 1 $ 2 Sen $ 3 Figure 4 Figure 5 M Kaya Otsu Close $ 7 Figure

Claims (1)

[Claims] In a vibration wave motor in which a toroidal stator and a toroidal rotor are brought into pressure contact with each other, the toroidal stator has a structure in which a vibrator that converts electrical vibration having a vibration waveform into mechanical vibration and a toric resonator are bonded together,
a fixed shaft fixed on the annular rotor shaft, into which the annular stator is fitted so as to be movable in the axial direction while being adjacent to the annular rotor, and having a threaded portion at an end; A spring washer having a female threaded portion and screwed onto the fixed shaft, and a compression spring provided between the annular stator and the spring washer to exert a pressing force on the annular stator. A vibration wave motor comprising an adjustable pressure mechanism.